The present invention generally pertains to wind tunnel testing. More particularly, the present invention pertains to a wind tunnel for the aerodynamic testing of vehicles. More specifically, but without restriction to the particular embodiment and/or use which is shown and described for purposes of illustration, the present invention relates to a multiple stage system for fluid flow velocity profile control on a fixed surface.
Modern motor vehicles are thoroughly tested during development in various extreme environments. Such testing includes wind tunnel testing during which a vehicle is subjected to an artificially created and controlled air flow.
It is a relatively straightforward matter to replicate a wind velocity experienced by a motor vehicle at a particular driving speed. However, the simulation of accurate driving conditions also requires, among other considerations, management of a boundary layer which would otherwise build up adjacent to a stationary platform supporting the vehicle. Such a boundary layer results in a slower flow of air adjacent the support surface that does not accurately simulate conditions experienced by a vehicle traveling over a road surface at the particular driving speed.
The inaccuracies attendant with boundary layer buildups have been overcome in the prior art through the incorporation of a continuous belt. The continuous belt is driven at a speed equal to the desired vehicle speed to thereby simulate relative movement between the vehicle and a road surface. Among other limitations, wind tunnel testing systems incorporating moving belts are complex, expensive, require continual maintenance, and can require significant vehicle modification prior to vehicle testing.
It is also known in the prior art to simulate relative movement between a vehicle to be tested and a stationary surface through the introduction of various mechanisms intended to either divert slower flowing air from adjacent the stationary surface or introduce a faster flow of air adjacent the stationary surface. While such arrangements overcome many of the drawbacks attended with moving belt systems, they have not been able to accurately simulate driving conditions. Explaining further, with such systems the velocity profile is often distorted as it passes along the length of the vehicle. It remains a need in the pertinent art to provide a system for aerodynamic testing of a vehicle without a moving belt which more accurately simulates driving conditions to be experienced by the vehicle at a predetermined vehicle speed.
In accordance with one aspect of the present invention, a method and apparatus are provided for more accurately simulating the aerodynamics of a moving road beneath a vehicle being tested in a wind tunnel without the need of a moving belt.
In accordance with another object of the present invention, a method and apparatus are provided for aerodynamic testing of a vehicle which establishes a reduced boundary layer formed under the vehicle under testing in the wind tunnel without distorting or overshooting a velocity profile.
Yet another aspect of the present invention is to provide a method and apparatus for testing a motor vehicle in a wind tunnel which does not require modification of the vehicle for mounting over a moving belt.
In one form, the present invention provides a method of aerodynamic testing a vehicle having a front pair of wheels and a rear pair of wheels. The method includes statically supporting the vehicle on a surface, and directing a primary source of air along the fixed surface towards the vehicle. The primary source of air simulates the aerodynamic conditions for the vehicle at a predetermined speed. A first supplemental source of air is introduced into a flow of air generated by the primary source of air along and parallel to the fixed surface immediately behind the first pair of wheels of the vehicle.
In another form, the present invention provides a system for aerodynamically testing a vehicle having a front pair of wheels and a rear pair of wheels. The system includes a surface for statically supporting the vehicle. The system additionally includes a primary source of air directed towards the vehicle. The primary source of air aerodynamically simulates conditions for the vehicle at a predetermined speed. The system further includes a first supplemental source of air directed into a flow of air generated by the primary source of air immediately behind the first pair of wheels.
Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which this invention relates from a reading of the subsequent description of the preferred embodiment and the appended claims, taken in conjunction with the accompanying drawings.